1. Field of the Invention
Since the introduction of the wheel and axle and the principle of the lever and fulcrum, engineers, designers, experimenters, inventors and others have tried to discover the secret of varying the output torque of an engine without changing gears and still be able to maintain an enmeshed gear train in the process.
The current invention covers improvements to a shiftless, continuously-variable transmission and is generally directed to power transmissions for automotive vehicles and also for heavy-duty equipment and off-highway vehicles which make use of torque converters, and more particularly, to those vehicles that shy away from automatic transmissions because of slippage in the torque converters.
This invention provides torque-increasing gearing that supplies a great work advantage for the turbine member of the torque converter, over and above that of the conventional converters, in its ability to develop high starting torque when needed and deliver it at variable output rates, which permits the turbine to operate at a much closer RPM to that of the impeller practically all the time to reduce slippage and help provide engine retardation in a drifting mode. The present transmission requires no sensors, modulators or governors to determine a shift in ratio, because it does not shift gears. It has no clutches except for engaging and disengaging the prime mover from the transmission gearing.
An overdrive planetary unit is included at the final drive and it is engaged at all times because the high torque ability of the turbine and gear train can provide sufficient torque in overdrive range to handle the work load, even at low speed and with excessive loading.
2. History of the Prior Art
There has been a lot of striving to create a truly variable ratio transmission that is efficient and possesses a broad ratio band and one that can stand up to high torque engines; but the only ones I have encountered are the CVT type with belts and variable pulleys and the hydrostatic type and both of these devices have great limitations. Some of the latest produced vehicles have a manual shift transmission endeavoring to get a better gas mileage efficiency. Some of the latest transmission designs to reach the market include computer technology to smooth out the shifts from one range to another; and some even account for wear of the clutch plates. I have found no record of patented transmissions using a fully enmeshed gear train that automatically varies the ratio by controlling the speed of the planetary ring gears to the optimum speed. Most are controlled by servo brake bands or clutches and operate like speed reducers and do not vary the output torque.